Author’s IntroductionIt is suggested that it is possible to give an analysis of the mental concepts as states of the person apt for producing certain ranges of behaviour. This analysis leaves it open what the concrete nature of the states is. But scientific considerations made it plausible that these states are purely physical states of the central nervous system. Special attention is given to the concept of consciousness, which is argued to be perception of our own mental state.

The paper first argues that the problem expressed by the sentence, "could mental states be brain processes" is not simply an empirical matter but involves a central conceptual problem.

It next argues for the conclusion that there is a conceptual problem for any version of the identity theory, namely that since brain processes and mental states each have properties not truly attributable to the other, then – by Leibniz's principle – they are not the same.

Finally, the paper proposes a way to avoid this conclusion by arguing that application of Leibniz's principle is unwarranted whenever its application involves a category mistake.

Philosophers Index AbstractMaintaining that the proper task of philosophy is to encourage the invention and refinement of new theories, the author defends materialism against three popular arguments. The first holds that materialism is inconsistent with ordinary usage and so cannot meaningfully be applied to human beings; the second argues from observation that thoughts are not material processes; the third asserts that people are directly acquainted with their own mental experiences. The author examines the logic and motivation of these arguments and concludes there is no reason to abandon the attempt to give a purely physiological account of human beings. (Staff)

It is first shown that J J C Smart's account of the meaning of reports of sensations in terms of physical stimulus conditions is defective.

It is then argued that no such materialistic manoeuvring can succeed, showing that we cannot avoid admitting the existence of nonphysical properties. However, it is added that these nonphysical properties need not be irreducibly different from physical properties.

The remainder of the paper is concerned, first, to defend the proposition that a convention could be adopted for locating mental events in the brain and, then, to describe conditions under which the identity theory is empirically refuted.